The present disclosure relates to a gas turbine engine and, more particularly, to a geared architecture with an additive manufactured gear therefor.
Epicyclical gear systems with planetary or star gearboxes may be used in gas turbine engines for their compact design and efficient high gear reduction capabilities. Planetary and star gearboxes generally include three gear train elements: a central sun gear, an outer ring gear with internal gear teeth, and a plurality of planet gears supported by a planet carrier between, and in meshed engagement with, both the sun gear and the ring gear. The gear train elements share a common longitudinal central axis, about which at least two rotate.
In a star gear design, the planet carrier is stationary and the output shaft is driven by the ring gear in a direction opposite that of the sun gear. In a planetary gear design, the carrier rotates which may cause the weight of the planet gear to apply a centrifugal load to the planet bearing. In geared architecture gas turbine engines, this load may be significant and can even be higher than the total torque load of the engine.
In some current geared architectures, the star/planet gear rims include axial lightening apertures to reduce gear weight. This may be effective with relatively low load journal bearings or small diameters, however, as load or diameter increases, the difference in radial stiffness of the rim at the lightening apertures as compared to between the lightening apertures, may effect performance.